1. Field of the Invention
The present invention relates to a guiding apparatus and a method for cochlear implant, more particularly, for reducing injuries caused by an electrode to an inner wall of the cochlear canal during insertion and enabling the electrode to be properly located.
2. Description of the Related Technology
The cochlear, a human organ for the sense of hearing, looks like a snail-shaped tube having a length of about 3.5 cm and two and half turns.
And the cochlear implant system is a device for electrically stimulating auditory nerves of a patient who is profoundly deaf or severely hard of sensorineural hearing due to the injuries on a Corti organ in the inner ear or a deafness to deliver the signals to the cerebrum. That is, the cochlear implant system for sensorineural hearing loss or deafness converts sound into a weak electrical signal by use of a small-sized computer and provides the electrical signal directly to the auditory nerves according to a magnitude and a tone to deliver the sound to the cerebrum.
In 1967, professor Graeme Clark of Melbourne University started to study a hearing aid, and as many studies executed after 10-channel hearing aid had been transplanted to the first patient in 1978, there are about 50,000 cases until now.
The cochlear implant device has internally-implanted and external portion. The external component, being located at the outside, includes a microphone, a voice processor and an external coil. After processing a voice signal (i.e., sound) received by the microphone at the voice processor, the processed signal and a power for operating internal circuit are sent to the internally-implanted portion through the external coil.
The internally-implanted portion, being transplanted into the body, includes an internal circuit with a circuit and a stimulation chip, a package for sealing to protect the internal circuit from humoral materials and/or ions, an electrode to be inserted into the cochlear, and an internal coil for remotely controlling the stimulation chip and receiving the processed signal from the outside. The internal circuit, the package, the electrode and the internal coil are electrically coupled to each other. The signal from the external coil is received by the internal coil, and separated into a power signal to be used to operate itself and a nerve ganglion cell stimulation signal, which stimulates the nerve ganglion cell in the cochlear though the electrode so that the stimulated cell generates the electrical signal to be delivered to the brain via auditory nerve. By way of this, one who has difficulty in hearing or deafness can hear.
In an operation method for the cochlear implant system, the mastoid of a patient is grinded to expose the oval window of a cochlear canal where the electrode will be inserted and the very thin and long electrode that is about 10 mm in thickness and about 2˜2.5 cm in length is inserted into the cochlear canal.
Hereinafter, the conventional method for inserting the cochlear implant system will be briefly described with reference to FIG. 1 and FIG. 2.
FIG. 1 is a block diagram of the conventional device for inserting the cochlear implant system, and FIG. 2 shows a method for inserting the cochlear implant system.
Referring to FIG. 1 and FIG. 2, the conventional device comprises an electrode 110 and a guiding wire 120.
In the conventional method, a surgeon inserts the guiding wire 120, so-called stylet, into the electrode at step 150, and then selects a proper position in the cochlear canal based on his operation experiences and tactical sense at step 155. After locating the electrode 110 on the proper position at step 160, the electrode 110 is fixed in the cochlear canal by removing the guiding wire 120 at step 165.
In addition, a subsidiary (not shown) can be inserted into the cochlear canal and then the electrode can be inserted.
In the conventional technique, the electrode 110 has a curved shape in itself (not shown) and is maintained a straight line during insertion by the guiding wire 120 or the subsidiary for easy insertion. And, by removing the guiding wire 120 after inserting the electrode 110, the safe installation of the electrode in the cochlear canal and the easiness of operation can be accomplished.
But, since the conventional method is depending entirely on a surgeon's tactile sense, it is very difficult and complicated to insert the electrode.
Also, in the conventional method, there is a possibility to cause tissue injuries when inserting the cochlear implant system into the cochlear canal.
Furthermore, although the more the electrode is close to the central axis wall of a cochlear the more stimulation is effective in the conventional method, it is impossible to get information about the inserting route and the position of the electrode during the operation.